Headlight -lens



angles to the surface ofi the lens. Thus, light is thrown to the sidesof the lamp in its nnmediate vicinity; as this action is particularlyhelped by the ground part atV 9 on the bell which is in advance of thepla-ne oli the lens, This part also cuts oli' the direct for- Wardglarini rays from thevlamp C. r lhe action of di usion and reflection isindicated diagrammatically in Fig. l. All rays striking the groundsurface 7 are dill used and are thrown at different angles through thedass and against the front corrugations. l ovv these rays, beingprojected at di florent an J*les and strilcin Y the corrugation faces atdi terent an les see the left hand picture of Fig. 4) an the corriwationfaces being in intersecting planes, tlle result is that rays of lightare thrown out sidewise from the con rugation faces at ditl'erent anglesand these rays cross and interfere with each other t see the right handportieri of Fig. Ll). The re sult is that all points at the side of thelamp are lighted by numbers of ra 7s from dili'er ent points. The sideillumination 'is ei;- ceptionally uniform because the rays are veryuniformly distributed.

lt will be noted that While the ground surfaces of course dilfuse in alldirections, the corrugations dilfuse and deflect only horizontally.Then, all the light which strikes the ground surfaces is diffused to acertain extent in all directions, but mostly horizontally*7 and all suchlight, when thus diffused assists in illuminating the ground close toand at the side of the lamp. But it will be particularly noted that allli ght which would normally (by the reflection alone) be thrownupwardly, is diffused so as to be noinglaring. The small ground surfaceat lll performs particularly the function of dilusing that light whichwould normally be thrown down closest to the vehicle; and the groundsurfaces at 1l perform particularly the function of diffusing the lightfrom the center edge portions ol" the reflector and lens.

It' is obvious that l structure, which distributes the light in such away that it is unobjectionable tothe person in the ro'adway, whether onfoot or in other vehicles, and which distributes the light on the groundin the places most desired and "with the intensity most desired. ln factthe distribution is very even, and the light very intense, over a largearea Which is very nearly rectangular in form. The side illumination isvery goed, as is also the illumination far in advance of the vehicle,and an important feature is that the light is thrownstrongly' at rightangles to the have provided a lens foryvard direction, giving anillumination overa side area close to the vehicle.

Having described a preferred forni of' my invention, what l claim is:

l. A lens, comprising a transparent body havingr a vertically tintedsurface substantially entirely covering a face thereof, and a larethereofliaving clear and translcuent parts, the translucent partsurroundingl the clear part and the clear part comprising that part ofthe face which is bounded below by a line substantially horizontal andrhordal and near the center' oi the lens and bounded on opposite sidesby lines which have a general convergency 'from near the outer ends ofthe chordal boundary to a point near the vtop center of the lens; thetransparent body having a central v(lished part and said lower chordalboundary havingr a substantially central semifcircular up wardprojection into the dished part, so that the whole center portion of thedished part is translucent.

A lens, comprising a transparent body l'laving a vertical fluted surfacesubstann tially entirely covering a face thereof, and a face thereofhaving clear and `translucent parts, the translucent part surroundingthe clear part and the clear part comprising that part of the face whichis bounded bclow by a line substantially horizontal and chcndal and nearthe center of the lens and bounded on opposite sides by lines whichhave, a" general convergency from near the outer end of the chordalboundary to points near the top center of the lens; each of said sideboundary lines extending first generally upwardly from the end of thechordal boundary and then extending sharply inwardly and then upwardlyto the top of the lens, so that the clear portion of the lens issubstantially of the shape of an inverted T with a comparatively widepart below` and a comparatively narrow part above, which narrow part ismuch narrower horizontally in comparison with the horizontal width ofthe lens at that point than is the Wide part in comparison with thehorizontal width of the lens at its center; the lens having a central(lished portion and said lower chordal boundary having a substantiallycentral semicircular upward projection in the dished part, so that theWhole center portion of the dished part is translucent.

ln witness that i claim the foregoin I have hereunto subscribed my nainethis l21th day of December, 1918.

ADELBERT R. GIBSON. llVitness:

Vmomm I. Baumann.

